Integrating safe communication
Each safety option must be created by the user in the safety program. For establishing the operation of the safety function, defined variables are available that can be named differently depending on the Safety over EtherCAT® main device.
Example
The following example illustrates these variables on the basis of group ports from Beckhoff.
Variable | Function | |
|---|---|---|
Group ports for controlling | RUN/STOP | Starts/stops the execution of the Safety over EtherCAT® program. |
Err Ack | Error reset/acknowledgment of safe communication. | |
Module Fault | N.N. | |
Group ports for monitoring | FB Err | Error during execution of a function block. |
Com Err | Communication error. | |
Out Err | Output error. | |
Other Err | Other error. | |
Com Startup | Safe communication is established. | |
FB Inactive | N.N. | |
FB Run | Execution of function blocks is running. | |
In Run | Safety program is running. |
The procedure for starting the safety function and for reintegrating a safety device depends on the Safety over EtherCAT® main device and is not shown here.
Safety over EtherCAT® has validity information for its safe process data. This is transferred from main device to sub-device for the process output data and from sub-device to main device for the process input data when the safety protocol is established. If "Invalid" is reported by the main device, all process output data on the sub-device side is zeroed. The sub-device always reports "valid" with the current process input data.
